A formal request for a green card or a specific nonimmigrant visa, such as a student or business visa. When you file your petition, you must submit documents that prove you qualify for the status you wish to obtain. For example, if you obtain permission to attend a U.S. university, you must file a petition for a student visa with the U.S. embassy or consulate in your home country, including the documents that show you have been admitted to the school. After your petition is approved, you may submit your visa application.